At present Internet users can use the access links of multiple Internet service providers (ISP) to access the network services. Each ISP provides the users with its own Domain Name System (DNS) server and converts the Domain Name into the Internet Protocol (IP) address with DNS service. In addition, the application service providers also publish their own network services with multiple ISP links and take over the domain name resolution works with their own intelligent DNS server. The application service provider 15 publishes its own network services (such as WEB) with two ISP (marked as ISP1 and ISP2) networks (marked as 112 and 122) and resolves its own domain name with its own intelligent DNS server 152, as shown in FIG. 1. The rules for resolving domain names are when the source address requested by DNS is the IP address of the DNS server 111 of ISP1, the intelligent DNS returns the IP address of the network service on ISP1, while when the source address requested by DNS is the IP address of the DNS server 121 of ISP2, the intelligent DNS requires to return the IP address of the network service on ISP2. When the user equipments 14 (such as computers) are connected with the access links 113 and 123 of ISP1 and ISP2 through the access gateway equipments 13, multiple DNS servers IP can be set in the user equipments 14. However, the preferred DNS server is generally the only one selected to resolve the domain name, which means only if the preferred DNS server is failed to resolve, will the user equipments 14 select other DNS servers to carry out the resolution. For example, if the preferred DNS server in the user equipments 14 is the DNS server 111 of ISP1, the access gateway equipments 13 will forward the domain name resolution requests to the DNS server 111 after they have received those requests of the network services sent by the user equipments 14, then the DNS server 111 will send the domain name resolution requests to the intelligent DNS server 151 of the application service provider 15 and the intelligent DNS server 151 will return the IP address of the network services on ISP1 to the DNS server 111 according to the foregoing domain name resolution rules of the intelligent DNS server 151, then the IP address is sent form the DNS server 111 to the access gateway equipments 13 and is returned from the access gateway equipments 13 to the user equipments 14, and then the user equipments 14 will originate the network service access requests to the access gateway equipments 13 according to the IP address and the access gateway equipments 13 will visit the network services on the server 152 of the application service provider 15 through the access link 113 of ISP1 after they have identified that the IP address belongs to ISP1. In the network structure shown in FIG. 1, if the DNS server 111 of ISP1 is set to be the preferred DNS server in multiple user equipments 14 connected with the access gateway equipments 13, all user equipments 14 will visit the network services through the access link 113 of ISP1, thereby causing overloads and congestion on the access link 113 of ISP1 and reducing the access speed of network services.